1. Field of the Invention
The disclosure relates to a polarization modulation device and laser system thereof. Particularly, the disclosure relates to a polarization modulation device and laser system for wideband laser.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Wideband light source technique is one key technique in the advanced optical inspection field. Based on the need for miniaturization of semiconductor process and real-time inspection in bio-medical applications, the traditional detecting method is limited to low resolution. Conventional narrowband-wavelength light sources cannot provide advanced resolution for bio-medical instruments. One way to increase resolution is to use a wideband wavelength light source. A wideband wavelength light source has shorter interferometric wavelength and lower coherency so as to have higher resolution. Thus, wideband light sources have been applied for optical coherence tomography for detecting eyes and eye cells. Therefore, the advanced optical inspection field still intends to focus on development of a stable wideband light source with high bandwidth.
Although the wideband light emitting diode usually serves as a light source, the beam quality and coupling efficiency of the wideband light emitting diode are poor. In addition, the semiconductor laser source has a low resolution due to narrow bandwidth so that the wavelength of the semiconductor laser source cannot cover several applicable wavelength ranges. Because the Femto second scale laser system is very expensive and unstable due to environmental sensitivity, the optical coherence tomography field still needs a new wideband laser light source to solve the above-mentioned defects of traditional laser systems.